General developmental defects of grechetto mutants. (A-B) Live bright-field image of a 5 dpf WT sibling (A) and of a grechetto mutant (B). Lateral view, anterior to the left, dorsal upward. The mutant shows a curved body, cardiac edema, lack of an inflated swim bladder, smaller head and eyes, and reduced melanophores in the lateral stripes compared with the WT sibling. (C-F) Dorsal view, anterior to the left, of a 5 dpf WT sibling (C,E) and of a grechetto mutant (D,F) shown in transmitted light (C-D) or epi-illumination (E-F). grechetto mutants show smaller lateral fins (D arrows), aberrant melanophores (D insets), and markedly reduced iridophore cell numbers in the dorsal stripe (F) compared with their WT siblings. (G-J) Alcian Blue staining of the jaw cartilages of a 5 dpf WT sibling (G,I) and of a grechetto mutant (H,J) shown in lateral (G-H) or ventral (I-J) views. ch indicates ceratohyal; cb, ceratobranchial; eth, ethmoidal; Mk, Meckel; and qu, palatoquadrate. grechetto mutants show abnormal development of the posterior ceratohyal and ceratobranchial cartilages.